mol-plugin: Fixed a bug in Select param control

src/mol-plugin/ui/controls/parameters.tsx

@@ -221,7 +221,7 @@ export class SelectControl extends SimpleParam<PD.Select<string | number>> {
     }
     renderControl() {
         const isInvalid = this.props.value !== void 0 && !this.props.param.options.some(e => e[0] === this.props.value);
-        return <select value={this.props.value || this.props.param.defaultValue} onChange={this.onChange} disabled={this.props.isDisabled}>
+        return <select value={this.props.value !== void 0 ? this.props.value : this.props.param.defaultValue} onChange={this.onChange} disabled={this.props.isDisabled}>
             {isInvalid && <option key={this.props.value} value={this.props.value}>{`[Invalid] ${this.props.value}`}</option>}
             {this.props.param.options.map(([value, label]) => <option key={value} value={value}>{label}</option>)}
         </select>;